Aminothiadiazoles and their use for controlling undesirable plant growth

ABSTRACT

Aminothiadiazoles of the formula ##STR1## where R 1 , R 2 , A, X, Z, m and n have the meanings given in the description, are used for controlling undesirable plant growth.

This application is a continuation of application Ser. No. 457,179, filed on Jan. 11, 1983 now abandoned.

The present invention relates to aminothiadiazoles, herbicides which contain these compounds as active ingredients, and a method of controlling undesirable plant growth with these compounds.

2-Amino-5-phenoxymethyl-1,3,4-thiadiazoles have been disclosed as intermediates for the synthesis of herbicidal 3-(5-phenoxymethyl-1,3,4-thiadiazol-2-yl)imidazolidinones (U.S. Pat. No. 4,252,961). Moreover, it has been disclosed that 2-amino-5-phenyl(alkyl)-1,3,4-thiadiazoles possess pharmacological activity (German Laid-Open Application Nos. DOS 2,212,245, DOS 2,510,439 and DOS 2,126,261). German Laid-Open Application No. DOS 2,336,407 describes herbicidal 2-amino-5-benzyl-1,3,4-thiadiazoles, but these compounds are only effective when applied preemergence.

We have found that aminothiadiazoles of the formula ##STR2## where R¹ and R² independently of one another are each hydrogen, C₁ -C₁₀ -alkyl, C₃ -C₈ -cycloalkyl, C₂ -C₅ -alkoxyalkyl, phenyl, benzyl or 2-phenylethyl, or R¹ and R² together form an alkylene chain of no more than 6 carbon atoms which is unsubstituted or substituted by C₁ -C₄ -alkyl and may or may not contain oxygen as a chain member, A is an alkylene chain of 1 to 8 carbon atoms which is unsubstituted or substituted by C₁ -C₄ -alkyl, Z is oxygen or sulfur, n is 0 or 1, X is halogen, cyano, nitro, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, C₁ -C₄ -haloalkyl, C₁ -C₄ -haloalkoxy, C₁ -C₄ -alkylthio, C₁ -C₄ -alkylsulfonyl, C₃ -C₆ -cycloalkyl, phenyl or unsubstituted or halogen-substituted aryloxy, and m is 0, 1, 2, 3 or 4, and where the radical ##STR3## can be replaced by naphthyl which is unsubstituted or substituted by halogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, with the proviso that R¹ and R² are not both hydrogen when n is 0 and A is --CH₂ --, have a herbicidal action and selectively control undesirable plant growth in crop plants.

Novel aminothiadiazoles are those of the formula ##STR4## where R¹ and R² independently of one another are each hydrogen, C₁ -C₁₀ -alkyl, C₃ -C₈ -cycloalkyl, C₂ -C₅ -alkoxyalkyl, phenyl, benzyl or 2-phenylethyl, or R¹ and R² together form an aklylene chain of no more than 6 carbon atoms which is unsubstituted or substituted by C₁ -C₄ -alkyl and may or may not contain oxygen as a chain member, A is an alkylene chain of 1 to 8 carbon atoms which is unsubstituted or substituted by C₁ -C₄ -alkyl, Z is oxygen or sulfur, n is 0 or 1, X is halogen, cyano, nitro, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, C₁ -C₄ -haloalkyl, C₁ -C₄ -haloalkoxy, C₁ -C₄ -alkylthio, C₁ -C₄ -alkylsulfonyl, C₃ -C₆ -cycloalkyl, phenyl or unsubstituted or halogen-substituted aryloxy and m is 0, 1, 2, 3 or 4, and where the radical ##STR5## can be replaced by naphthyl which is unsubstituted or substitued by halogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, with the proviso that R¹ and R² are not both hydrogen when n is 0, and that R² is not hydrogen, n-butyl, allyl, cyclohexyl or phenyl when R¹ is hydrogen and A is methylene which is unsubstituted or substituted by C₁ -C₄ -alkyl.

In formulae I and Ia, R¹ and R² independently of one another may be hydrogen, C₁ -C₁₀ -alkyl, preferably C₁ -C₄ -alkyl, eg. methyl, ethyl, n-propyl, i-propyl, t-butyl or n-decyl, C₃ -C₈ -cycloalkyl, eg. cyclopropyl, cyclohexyl or cyclooctyl, C₂ -C₅ -alkoxyalkyl, eg. methoxyethyl or n-propoxyethyl, phenyl, benzyl or 2-phenylethyl, or R¹ and R² together can form an alkylene chain of no more than 6 carbon atoms which is unsubstituted or monosubstituted or polysubstituted by C₁ -C₄ -alkyl, preferably by methyl, and may or may not contain oxygen as a chain member, eg. butylene, pentylene, 1,4-dimethylbutylene, 3-oxapentylene or 2,4-dimethyl-3-oxapentylene, A is an unsubstituted or C₁ -C₄ -alkyl-substituted alkylene chain or 1 to 8 carbon atoms, eg. methylene, methylmethylene, ethylene, methylethylene, dimethylmethylene, dimethylethylene, porpylene, methylpropylene, ethylmethylene, butylene, pentylene, hexylene, heptylene, methylbutylene or octylene, X is halogen, eg. chlorine, bromine, fluorine or iodine, cyano, nitro, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, C₁ -C₄ -alkylthio, C₁ -C₄ -haloalkyl, C₁ -C₄ -haloalkoxy, C₁ -C₄ -alkylsulfonyl, C₃ -C₆ -cycloalkyl, phenyl or unsubstituted or halogen-substituted aryloxy, such as unsubstituted or halogen-substituted phenoxy, eg. methyl, ethyl, t-butyl, methoxy, ethoxy, t-butoxy, n-hexyloxy, methylthio, ethylthio, n-butylthio, trifluoromethyl, difluoromethoxy, 1,1,2-trifluoro-2-chloroethoxy, methylsulfonyl, cyclopentyl, cyclohexyl, phenoxy, 4-chlorophenoxy or 2,4-dichlorophenoxy, and Z is oxygen or sulfur.

In formula I, the radical ##STR6## may furthermore be replaced by α- or β-naphthyl which is unsubstituted or substituted by halogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, eg. α-naphthyl, β-naphthyl, 4-chloro-α-naphthyl, 7-methoxy-α-naphthyl or 2-methyl-α-naphthyl.

Preferred aminothiadiazoles of the formula Ia are those in which R¹ is hydrogen, R² is C₁ -C₄ -alkyl, A is an alkylene chain of 1 to 4 carbon atoms, n is 0 or 1, Z is oxygen, X is halogen or C₁ -C₄ -alkyl and m is 1, 2 or 3, and preferred aminothiadiazoles of the formula I are those in which R¹ is hydrogen, R² is C₁ -C₄ -alkyl, A is an alkylene chain of 2 to 4 carbon atoms, n is 0 or 1, Z is oxygen, X is halogen or C₁ -C₄ -alkyl and m is 1, 2 or 3.

The aminothiazoles of the formula I are obtained by a process wherein a carboxylic acid of the formula ##STR7## where A, X, Z, m and n have the above meanings, is reacted with a thiosemicarbazide of the formula ##STR8## where R¹ and R² have the above meanings.

This reaction can be carried out in the presence of a solvent which is inert under the reaction conditions, suitable solvents being hydrocarbons, eg. gasoline, toluene and cyclohexane, halohydrocarbons, eg. methylene chloride, chlorobenzene and dichlorobenzene, and ethers, eg. tetrahydrofuran and dioxane. The reaction is carried out at from 0° to 150° C., preferably from 40° to 120° C. It is advantageous to add an agent which eliminates water, eg. sulfuric acid, hydrofluoric acid, polyphosphoric acid, phosphorus pentoxide or phosphorus oxychloride.

EXAMPLE 1

6 g of phosphorus oxychloride were added dropwise, in the course of half an hour, to 25 g of ω-4-chlorophenoxybutyric acid, 10.6 g of thiosemicarbazide and 250 g of dioxane, at 90° C., after which the mixture was stirred under reflux for 1 hour, cooled and then evaporated down in a rotary evaporator. The residue was stirred with water and sufficient sodium hydroxide solution to bring the pH to about 10. The precipitated crystals were filtered off under suction and dried, and the white substance obtained had a melting point of 188°-190° C. and was of the following formula ##STR9## The aminothiadiazoles below, of the formula I or Ia, are prepared by a similar procedure.

    __________________________________________________________________________      No.                                                                                A          Z.sub.n                                                                          X.sub.m                                                                                  ##STR10##   M.p. [°C.]                      __________________________________________________________________________     2   CH.sub.2   O 4-Cl      NHCH.sub.3  138-140                                 3   CH.sub.2   O 4-Cl      NH.sub.2    215-217                                 4   CH.sub.2   --                                                                               4-phenyl  NHCH.sub.3  165-167                                 5   CH.sub.2   --                                                                               4-phenyl  NH.sub.2    229-231                                 6   CH.sub.2   --                                                                               H         NHCH.sub.3  117-118                                 7   CH.sub.2   --                                                                               H         NH.sub.2    178-180                                 8   (CH.sub.2).sub.3                                                                          O 4-Cl      NHCH.sub.3  105-107                                 9   (CH.sub.2).sub.3                                                                          O 4-Cl      NHC.sub.2 H.sub.5                                                                          98-99                                   10  (CH.sub.2).sub.3                                                                          --                                                                               H         NHCH.sub.3  56-58                                   11  (CH.sub.2).sub.3                                                                          --                                                                               H         NH.sub.2    180-182                                 12  (CH.sub.2).sub.4                                                                          O 4-Cl      NHCH.sub.3  83-85                                   13  (CH.sub.2).sub.4                                                                          O 4-Cl      NH.sub.2    157-160                                 14   (CH.sub.2).sub.2                                                                         O 4-C.sub.4 H.sub.9tert.                                                                   NHCH.sub.3  114-116                                 15  (CH.sub.2).sub.3                                                                          O 4-C.sub.4 H.sub.9tert.                                                                   NH.sub.2    194-196                                 16  (CH.sub.2).sub.3                                                                          O H         NHCH.sub.3  88-90                                   17  (CH.sub.2).sub.3                                                                          O 4-C.sub.2 H.sub.5                                                                        NH.sub.2    178-180                                 18  (CH.sub.2).sub.3                                                                          O 4-CH.sub.3 O                                                                             NH.sub.2    186-188                                 19  (CH.sub.2).sub.3                                                                          O 4-Br      NH.sub.2    200-202                                 20  (CH.sub.2).sub.3                                                                          O 3-F       NH.sub.2    172-174                                 21  (CH.sub.2).sub.3                                                                          O 2-Cl      NH.sub.2    184-186                                 22  (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             NH.sub.2    164-166                                 23  (CH.sub.2).sub.3                                                                          O 3,5-Cl.sub.2                                                                             NH.sub.2    171-172                                 24  (CH.sub.3).sub.3                                                                          O 4-CN      NH.sub.2    154-156                                 25  (CH.sub.2).sub.3                                                                          O 3-CH.sub.3                                                                               NH.sub.2    180-182                                 26  (CH.sub.2).sub.3                                                                          O 4-CH.sub.3                                                                               NH.sub.2    197-200                                 27  (CH.sub.2).sub.3                                                                          O 3-Cl      NH.sub.2    149-150                                 28  (CH.sub. 2).sub.3                                                                         O 3-CH.sub.3                                                                               NHCH.sub.3  108-110                                 29  (CH.sub.2).sub.3                                                                          O 3-Cl      NHCH.sub.3  85-86                                   30  (CH.sub.2).sub.3                                                                          O 4-CH.sub.3                                                                               NHCH.sub.3  115-117                                 31  (CH.sub.2).sub.3                                                                          O 2-Cl      NHCH.sub.3  68-70                                   32  (CH.sub.2).sub.3                                                                          O 4-NO.sub.2                                                                               NHCH.sub.3  135-137                                 33  (CH.sub.2).sub.3                                                                          O 4-CN      NHCH.sub.3  119-121                                 34  (CH.sub.2).sub.3                                                                          O 4-Br      NHCH.sub.3  138-140                                 35  (CH.sub.2).sub.3                                                                          O 4-OCH.sub.3                                                                              NHCH.sub.3  110-112                                 36  (CH.sub.2).sub.3                                                                          O 4-t-C.sub.4 H.sub.9                                                                      NHCH.sub.3  107-109                                 37  (CH.sub.2).sub.3                                                                          O 4-C.sub.2 H.sub.5                                                                        NHCH.sub.3  100-102                                 38  (CH.sub.2).sub.3                                                                          O 3-CF.sub.3                                                                               NHCH.sub.3  78-80                                   39  (CH.sub.2).sub.3                                                                          O 3,5-Cl.sub.2                                                                             NHCH.sub.3  89-90                                   40  (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             NHCH.sub.3  103-105                                 41  (CH.sub.2).sub.3                                                                          O 2-CH.sub.3                                                                               NHCH.sub.3  84-86                                   42  (CH.sub.2).sub.3                                                                          O 3-F       NHCH.sub.3  72-74                                   43  (CH.sub.2).sub.3                                                                          O 2,4-Cl.sub.2                                                                             NHCH.sub.3  118-120                                 44  (CH.sub.2).sub.3                                                                          O 2-CH.sub.3, 4-Cl                                                                         NHCH.sub.3  134-138                                 45  CH(CH.sub.3)CH.sub.2 CH.sub.2                                                             O 4-Cl      NHCH.sub.3  109-111                                 46  CH(CH.sub.3)CH.sub.2                                                                      --                                                                               H         NHCH.sub.3  83-85                                   47  CH(CH.sub.3)CH.sub.2                                                                      --                                                                               4-NO.sub.2                                                                               NHCH.sub.3  132-135                                 48  CH.sub.2   --                                                                               4-Cl      NHCH.sub.3  134-136                                 49  CH.sub.2   --                                                                               2,4-Cl.sub.2                                                                             NHCH.sub.3  128-130                                 50  CH.sub.2   --                                                                               3-CH.sub.3                                                                               NHCH.sub.3  95-96                                   51  CH.sub.2   --                                                                               4-OCH.sub.3                                                                              NHCH.sub.3  124-125                                 52  CH.sub.2   --                                                                               3-CF.sub.3                                                                               NHCH.sub.3  75-76                                   53  CH.sub.2   --                                                                               3-OCH.sub.3                                                                              NHCH.sub.3  85-87                                   54  CH.sub.2   --                                                                               2-Cl      NHCH.sub.3  102-104                                 55  CH.sub.2   --                                                                               2-OCH.sub.3                                                                              NHCH.sub.3  116-117                                 56  CH.sub.2   --                                                                               4-CH.sub.3                                                                               NHCH.sub.3  112-114                                 57  CH.sub.2   --                                                                               2-NO.sub.2                                                                               NHCH.sub.3  68-71                                   58  CH(C.sub.2 H.sub.5)                                                                       --                                                                               H         NHCH.sub.3   99-100                                 59  CH.sub.2 CH.sub.2                                                                         --                                                                               H         NHCH.sub.3  102-104                                 60  C(CH.sub.3).sub.2 CH.sub.2                                                                --                                                                               H         NHCH.sub.3  147-150                                 61  C(CH.sub.3).sub.2 CH.sub.2                                                                --                                                                               4-CH.sub.3                                                                               NHCH.sub.3  132-135                                 62                                                                                  ##STR11## --                                                                               4-t-C.sub.4 H.sub.9                                                                      NHCH.sub.3  96-97                                   63  CH.sub.2   O 2,4-Cl.sub.2                                                                             NHCH.sub.3  141-142                                 64  CH.sub.2   O 2-CH.sub.3, 4-Cl                                                                         NHCH.sub.3  120-122                                 65  CH.sub.2   S 2-CH.sub.3, 4-Cl, 5-CH.sub.3                                                             NHCH.sub.3  155-158                                 66  CH(CH.sub.3)                                                                              O 2-CH.sub.3, 4-Cl                                                                         NHCH.sub.3  oil                                     67  CH.sub.2CH.sub.2                                                                          O H         NHCH.sub.3   98-101                                 68  CH.sub.2CH.sub.2                                                                          O 4-Cl      NHCH.sub.3  114-116                                 69  (CH.sub.2).sub.3                                                                          --                                                                               4-OCH.sub.3                                                                              NHCH.sub.3  79-81                                   70  (CH.sub.2).sub.4                                                                          --                                                                               H         NHCH.sub. 3 77-79                                   71  (CH.sub.2).sub.4                                                                          --                                                                               4-CH.sub.3                                                                               NHCH.sub.3  103-105                                 72  (CH.sub.2).sub.3                                                                          O 4-i-C.sub.3 H.sub.7                                                                      NHCH.sub.3  74-76                                   73  (CH.sub.2).sub.4                                                                          O H         NHCH.sub.3   98-100                                 74  (CH.sub.2).sub.2                                                                          --                                                                               H         NH.sub.2    178-180                                 75  (CH.sub.2).sub.4                                                                          O 2,4-Cl.sub.2                                                                             NHCH.sub.3  74-76                                   76  (CH.sub.2).sub.4                                                                          O 2-CH.sub.3, 4-Cl                                                                         NHCH.sub.3  74-76                                   77  (CH.sub.2).sub.4                                                                          O 2-CH.sub.3                                                                               NHCH.sub.3  69-71                                   78  (CH.sub.2).sub.4                                                                          O 3,4-Cl.sub.2                                                                             NHCH.sub.3  80-82                                   79  (CH.sub.2).sub.4                                                                          O 2-CH.sub.3                                                                               NH.sub.2    143-145                                 80  (CH.sub.2).sub.4                                                                          O 3,4-Cl.sub.2                                                                             NH.sub.2    135-137                                 81  (CH.sub.2).sub.4                                                                          O 3-CH.sub.3                                                                               NH.sub.2                                            82  (CH.sub.2).sub.4                                                                          O 3-CH.sub.3                                                                               NHCH.sub.3  70-71                                   83  (CH.sub.2).sub.4                                                                          O H         NHC.sub.2 H.sub.5                                                                          94-96                                   84  (CH.sub.2).sub.4                                                                          O 2-CH.sub.3                                                                               NHC.sub. 2 H.sub.5                                                                         57-59                                   85  (CH.sub.2).sub.4                                                                          O 3,4-Cl.sub.2                                                                             NHC.sub.2 H.sub.5                                                                          96-97                                   86  (CH.sub.2).sub.4                                                                          O 3-t-C.sub.4 H.sub.9                                                                      NHCH.sub.3  58-60                                   87  (CH.sub.2).sub.5                                                                          --                                                                               4-CH.sub.3                                                                               NHCH.sub.3  64-66                                   88  (CH.sub.2).sub.4                                                                          --                                                                               H         N(CH.sub.3).sub.2                                                                          oil                                     89  (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             N(CH.sub.3).sub.2                                                                           98-100                                 90  (CH.sub.2).sub.4                                                                          O 3,4-Cl.sub.2                                                                             N(CH.sub.3).sub.2                                                                          oil                                     91  (CH.sub.2).sub.4                                                                          --                                                                               H         N(C.sub.2 H.sub.5).sub.2                                                                   oil                                     92  (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             N(C.sub.2 H.sub. 5).sub.2                                                                  40-42                                   93  (CH.sub.2).sub.4                                                                          O 3,4-Cl.sub.2                                                                             N(C.sub.2 H.sub.5).sub.2                                                                   oil                                     94  (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             pyrrolidine 117-119                                 95  (CH.sub.2).sub.4                                                                          O 3,4-Cl.sub.2                                                                             pyrrolidine oil                                     96  (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             piperidine  84-85                                   97  (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             morpholine  96-97                                   98  (CH.sub.2).sub.4                                                                          --                                                                               H         pyrrolidine 68-70                                   99  (CH.sub.2).sub.4                                                                          --                                                                               H         piperidine  45-47                                   100 (CH.sub.2).sub.4                                                                          --                                                                               H         morpholine  62-64                                   134 CH.sub.2   --                                                                               3,5-(CH.sub.3).sub.2                                                                     NHCH.sub.3  108-110                                 141 (CH.sub.2).sub.4                                                                          O 3-Cl      NHCH.sub.3  75-77                                   142 (CH.sub.2).sub.4                                                                          O 4-Br      NHCH.sub.3  101-103                                 143 (CH.sub.2).sub.4                                                                          O 3-Br      NHCH.sub.3  79-81                                   145 (CH.sub.2).sub.4                                                                          O 3,5-(CH.sub.3).sub.2                                                                     NHCH.sub.3  66-67                                   147 (CH.sub.2).sub.4                                                                          O 3-OCH.sub.3                                                                              NHCH.sub.3  oil                                     148 (CH.sub.2).sub.4                                                                          O 3,5-Cl.sub.2                                                                             NHCH.sub.3  65-66                                   149 (CH.sub.2).sub.4                                                                          O 2,5-Cl.sub.2                                                                             NHCH.sub.3  76-77                                   150 (CH.sub.2).sub.4                                                                          O 3-NO.sub.2                                                                               NHCH.sub.3   99-101                                 151 (CH.sub.2).sub.4                                                                          O 2-Cl      NHCH.sub.3  77-78                                   156 (CH.sub.2).sub.6                                                                          O 3,4-Cl.sub.2                                                                             NHCH.sub.3  81-83                                   157 (CH.sub.2).sub. 5                                                                         O 3,4-Cl.sub.2                                                                             NHCH.sub.3  84-86                                   158 (CH.sub.2).sub.7                                                                          O 3,4-Cl.sub.2                                                                             NHCH.sub.3  78-80                                   166 (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             NH-phenyl   145-147                                 167 (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             NH-benzyl   125-126                                 168 (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             NHCH.sub.2 CH.sub.2phenyl                                                                  66-67                                   189 (CH.sub.2).sub.3                                                                          O 3,5-Cl.sub.2                                                                             N(i-C.sub.3 H.sub.7).sub.2                                                                 78-80                                   190 (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             NH(cycl-C.sub.6 H.sub.11)                                                                  85-86                                   191 (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             N(CH.sub.3)phenyl                                                                          85                                      192 (CH.sub.2).sub.3                                                                          O 3,4-Cl.sub.2                                                                             NH(i-C.sub.3 H.sub.7)                                                                      117-118                                 193 (CH.sub.2).sub.4                                                                          O 3,4-(CH.sub.3).sub.2                                                                     NHCH.sub.3  97-98                                   194 (CH.sub.2).sub.4                                                                          --                                                                               4-Cl      NHCH.sub.3  oil                                     195 (CH.sub.2).sub.4                                                                          --                                                                               4-OCH.sub.3                                                                              NHCH.sub.3  oil                                     198 (CH.sub.2).sub.5                                                                          --                                                                               4-Cl      NHCH.sub.3  172-175                                 __________________________________________________________________________

    ______________________________________                                          No.  A          Z.sub.n                                                                              ##STR12##                                                                                ##STR13##                                                                             M.p. [°C.]                      ______________________________________                                         184  (CH.sub.2).sub.3                                                                          O     α-naphthyl                                                                         NHCH.sub.3                                                                            108-110                                 185  (CH.sub.2).sub.3                                                                          O     β-naphthyl                                                                          NHCH.sub.3                                                                            114-116                                 186  (CH.sub.2).sub.3                                                                          O     β-naphthyl                                                                          NH.sub.2                                                                              176-178                                 187  (CH.sub.2).sub.4                                                                          O     α-naphthyl                                                                         NHCH.sub.3                                                                            105-107                                 188  (CH.sub.2).sub.4                                                                          O     β-naphthyl                                                                          NHCH.sub.3                                                                            123-125                                 ______________________________________                                    

The following aminothiadiazoles of the formula I or Ia may be obtained analogously:

    __________________________________________________________________________      No.                                                                               A            Z.sub.n                                                                          X.sub.m                                                                                    ##STR14##                                       __________________________________________________________________________     101                                                                               (CH.sub.2).sub.4                                                                            O 2,4,5-Cl.sub.3                                                                             NHCH.sub.3                                       102                                                                               CH.sub.2     O 4-NO.sub.2  NHCH.sub.3                                       103                                                                               C(CH.sub.3).sub.2                                                                           O 2-CH.sub.3  NHCH.sub.3                                       104                                                                               (CH.sub.2).sub.6                                                                            --                                                                               H           NHCH.sub.3                                       105                                                                               (CH.sub.2).sub.6                                                                            O H           NHCH.sub.3                                       106                                                                               CH.sub.2     S 4-Cl        NHCH.sub.3                                       107                                                                               CH.sub.2CH.sub.2 CH(CH.sub.3)                                                               O 4-Cl        NHCH.sub.3                                       108                                                                               (CH.sub.2).sub.3                                                                            O 4-F         NHCH.sub.3                                       109                                                                               (CH.sub.2).sub.3                                                                            O 2-F         NHCH.sub.3                                       110                                                                               (CH.sub.2).sub.3                                                                            O 4-I         NHCH.sub.3                                       111                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        NHC.sub.3 H.sub.7                                112                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        NHi-C.sub.3 H.sub.7                              113                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        NHC.sub.4 H.sub.9                                114                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        NHt-C.sub.4 H.sub.9                              115                                                                               (CH.sub.2).sub.3                                                                            O 4-CF.sub.3  NHCH.sub.3                                       116                                                                               (CH.sub.2).sub.3                                                                            O 4-C.sub.5 H.sub.9                                                                          NHCH.sub.3                                       117                                                                               (CH.sub.2).sub.3                                                                            O 4-C.sub.6 H.sub.13                                                                         NHCH.sub.3                                       118                                                                               (CH.sub.2).sub.3                                                                            O 4-(4'-chlorophenoxy)                                                                       NHCH.sub.3                                       119                                                                               (CH.sub.2).sub.3                                                                            O 4-(2',4'-dichlorophenoxy)                                                                  NHCH.sub.3                                       120                                                                               (CH.sub.2).sub.3                                                                            O 4-phenoxy   NHCH.sub.3                                       121                                                                               (CH.sub.2).sub.3                                                                            O 3-OC.sub.2 H.sub.5                                                                         NHCH.sub.3                                       122                                                                               (CH.sub.2).sub.3                                                                            O 4-OCHF.sub.2                                                                               NHCH.sub.3                                       123                                                                               (CH.sub.2).sub.3                                                                            O 3-OCF.sub.2 CHFCl                                                                          NHCH.sub.3                                       124                                                                               (CH.sub.2).sub.3                                                                            O 4-SC.sub.4 H.sub.9                                                                         NHCH.sub.3                                       125                                                                               (CH.sub.2).sub.3                                                                            O H           NH.sub.2                                         126                                                                               (CH.sub.2).sub.2                                                                            O 4-Cl        NH.sub.2                                         127                                                                               (CH.sub.2).sub.2                                                                            O 4-Cl        NHC.sub.2 H.sub.5                                128                                                                               (CH.sub.2).sub.3                                                                            O 3-NO.sub.2  NHCH.sub.3                                       129                                                                               (CH.sub.2).sub.3                                                                            S H           NHCH.sub.3                                       130                                                                               (CH.sub.2 ).sub.3                                                                           S 4-Cl        NHCH.sub.3                                       131                                                                               (CH.sub.2).sub.3                                                                            O 4-SCH.sub.3 NHCH.sub.3                                       132                                                                               (CH.sub.2).sub.3                                                                            O 4-SO.sub.2 CH.sub.3                                                                        NHCH.sub.3                                       133                                                                               CH.sub.2     --                                                                               2-CH.sub.3  NHCH.sub.3                                       135                                                                               CH.sub.2     --                                                                               3,5-Cl.sub.2                                                                               NHCH.sub.3                                       136                                                                               CH.sub.2CH.sub.2                                                                            --                                                                               3,4-Cl.sub.2                                                                               NHCH.sub.3                                       137                                                                               CH.sub.2     O 2,4,5-Cl.sub.2                                                                             NHCH.sub.3                                       138                                                                                ##STR15##   O 2,4-Cl.sub.2                                                                               NHCH.sub.3                                       139                                                                               (CH.sub.2).sub.3                                                                            O 2,6-(CH.sub.3).sub.2                                                                       NHCH.sub.3                                       140                                                                               (CH.sub.2).sub.4                                                                            O 4-t-C.sub.4 H.sub.9                                                                        NHCH.sub.3                                       144                                                                               (CH.sub.2).sub.4                                                                            O 3-CF.sub.3  NHCH.sub.3                                       146                                                                               (CH.sub.2).sub.4                                                                            O 4-OCH.sub.3 NHCH.sub.3                                       152                                                                               (CH.sub.2).sub.4                                                                            O 2,6-(CH.sub.3).sub.2                                                                       NHCH.sub.2                                       153                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                               N(i-C.sub.3 H.sub.7).sub.2                       154                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                               piperidine                                       155                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                               morpholine                                       159                                                                               (CH.sub. 2).sub.3                                                                           O 4-Cl        N(CH.sub.3).sub.2                                160                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        N(C.sub.2 H.sub.5).sub.2                         161                                                                               (CH.sub.2).sub.3                                                                            0 4-Cl        pyrrolidine                                      162                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        piperdidine                                      163                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        morpholine                                       164                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        NH-phenyl                                        165                                                                               (CH.sub.2).sub.3                                                                            O 4-Cl        N(CH.sub.3)phenyl                                169                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                               NHn-C.sub.10 H.sub.22                            170                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                               NHcycl.C.sub.6 H.sub.11                          171                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                               NHCH.sub.2 CH.sub.2 OCH.sub.3                    172                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                               NHcycl.C.sub.3 H.sub.5                           173                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                                ##STR16##                                       174                                                                               (CH.sub.2).sub.4                                                                            O 3,4-Cl.sub.2                                                                                ##STR17##                                       175                                                                               (CH.sub. 2).sub.4                                                                           S 4-Cl        NHCH.sub.3                                       176                                                                               (CH.sub.2).sub.4                                                                            --                                                                               4-CH.sub.3  N(CH.sub.3).sub.2                                177                                                                               (CH.sub.2).sub.4                                                                            --                                                                               4-CH.sub.3  N(C.sub.2 H.sub.5).sub.2                         178                                                                               (CH.sub.2).sub.4                                                                            --                                                                               4-CH.sub.3  pyrrolidine                                      179                                                                               (CH.sub.2).sub.4                                                                            --                                                                               4-CH.sub.3  piperidine                                       180                                                                               (CH.sub.2).sub.4                                                                            --                                                                               4-CH.sub.3  morpholine                                       181                                                                               (CH.sub.2).sub.3                                                                            O 4-OnC.sub.6 H.sub.13                                                                       NHCH.sub.3                                       182                                                                               (CH.sub.2).sub.3                                                                            O 4-cycl.C.sub.6 H.sub.11                                                                    NHCH.sub.3                                       183                                                                               (CH.sub.2).sub.3                                                                            O 4-Phenyl    NHCH.sub.3                                       196                                                                               (CH.sub.2).sub.4                                                                            --                                                                               3,4-Cl.sub.2                                                                               NHCH.sub.3                                       197                                                                               (CH.sub.2).sub.4                                                                            --                                                                               3,5-Cl.sub.2                                                                               NHCH.sub.3                                       __________________________________________________________________________

Compounds of formula I and Ia may be applied for instance in the form of directly sprayable solutions, powders, suspensions (including high-percentage aqueous, oily or other suspensions), dispersions, emulsions, oil dispersions, pastes, dusts, broadcasting agents, or granules by spraying, atomizing, dusting, broadcasting or watering. The forms of application depend entirely on the purpose for which the agents are being used, but they must ensure as fine a distribution of the active ingredients according to the invention as possible.

For the preparation of solutions, emulsions, pastes and oil dispersions to be sprayed direct, mineral oil fractions of medium to high boiling point, such as kerosene or diesel oil, further coal-tar oils, and oils of vegetable or animal origin, aliphatic, cyclic and aromatic hydrocarbons such as benzene, toluene, xylene, paraffin, tetrahydronaphthalene, alkylated naphthalenes and their derivatives such as methanol, ethanol, propanol, butanol, chloroform, carbon tetrachloride, cyclohexanol, cyclohexanone, chlorobenzene, isophorone, etc., and strongly polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, water, etc. are suitable.

Aqueous formulations may be prepared from emulsion concentrates, pastes, oil dispersions or wettable powders by adding water. To prepare emulsions, pastes and oil dispersions the ingredients as such or dissolved in an oil or solvent may be homogenized in water by means of wetting or dispersing agents, adherents or emulsifiers. Concentrates which are suitable for dilution with water may be prepared from active ingredient, wetting agent, adherent, emulsifying or dispersing agent and possibly solvent or oil.

Examples of surfactants are: alkali metal, alkaline earth metal and ammonium salts of ligninsulfonic acid, naphthalenesulfonic acids, phenolsulfonic acids, alkylaryl sulfonates, alkyl sulfates, and alkyl sulfonates, alkali metal and alkaline earth metal salts of dibutylnaphthalenesulfonic acid, lauryl ether sulfate, fatty alcohol sulfates, alkali metal and alkaline earth metal salts of fatty acids, salts of sulfated hexadecanols, heptadecanols, and octadecanols, salts of sulfated fatty alcohol glycol ethers, condensation products of sulfonated naphthalene and naphthalene derivatives with formaldehyde, condensation products of naphthalene or naphthalenesulfonic acids with phenol and formaldehyde, polyoxyethylene octylphenol ethers, ethoxylated isooctylphenol, ethoxylated octylphenol and ethoxylated nonylphenol, alkylphenol polyglycol ethers, tributylphenyl polyglycol ethers, alkylaryl polyether alcohols, isotridecyl alcohol, fatty alcohol ethylene oxide condensates, ethoxylated castor oil, polyoxyethylene alkyl ethers, ethoxylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, lignin, sulfite waste liquors and methyl cellulose.

Powders, dusts and broadcasting agents may be prepared by mixing or grinding the active ingredients with a solid carrier.

Granules, e.g., coated, impregnated or homogeneous granules, may be prepared by bonding the active ingredients to solid carriers. Examples of solid carriers are mineral earths such as silicic acid, silica gels, silicates, talc, kaolin, Attaclay, limestone, lime, chalk, bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate, magnesium sulfate, magnesium oxide, ground plastics, fertilizers such as ammonium sulfate, ammonium phosphate, ammonium nitrate, and ureas, and vegetable products such as grain flours, bark meal, wood meal, and nutshell meal, cellulosic powders, etc.

The formulations contain from 0.1 to 95, and preferably 0.5 to 90, % by weight of active ingredient.

Examples of formulations are given below.

I. 90 parts by weight of compound no. 1 is mixed with 10 parts by weight of N-methyl-alpha-pyrrolidone. A mixture is obtained which is suitable for application in the form of very fine drops.

II. 20 parts by weight of compound no. 3 is dissolved in a mixture consisting of 80 parts by weight of xylene, 10 parts by weight of the adduct of 8 to 10 moles of ethylene oxide and 1 mole of oleic acid-N-monoethanolamide, 5 parts by weight of the calcium salt of dodecylbenzenesulfonic acid, and 5 parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

III. 20 parts by weight of compound no. 5 is dissolved in a mixture consisting of 40 parts by weight of cyclohexanone, 30 parts by weight of isobutanol, 20 parts by weight of the adduct of 7 moles of ethylene oxide and 1 mole of isooctylphenol, and 10 parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and finely distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

IV. 20 parts by weight of compound no. 8 is dissolved in a mixture consisting of 25 parts by weight of cyclohexanol, 65 parts by weight of a mineral oil fraction having a boiling point between 210° and 280° C., and 10 parts by weight of the adduct of 40 moles of ethylene oxide and 1 mole of castor oil. By pouring the solution into 100,000 parts by weight of water and uniformly distributing it therein, an aqueous dispersion is obtained containing 0.02% by weight of the active ingredient.

V. 20 parts by weight of compound no. 7 is well mixed with 3 parts by weight of the sodium salt of diisobutylnaphthalene-alpha-sulfonic acid, 17 parts by weight of the sodium salt of a lignin-sulfonic acid obtained from a sulfite waste liquor, and 60 parts by weight of powdered silica gel, and triturated in a hammer mill. By uniformly distributing the mixture in 20,000 parts by weight of water, a spray liquor is obtained containing 0.1% by weight of the active ingredient.

VI. 3 parts by weight of compound no. 6 is intimately mixed with 97 parts by weight of particulate kaolin. A dust is obtained containing 3% by weight of the active ingredient.

VII. 30 parts by weight of compound no. 51 is intimately mixed with a mixture consisting of 92 parts by weight of powdered silica gel and 8 parts by weight of paraffin oil which has been sprayed onto the surface of this silica gel. A formulation of the active ingredient is obtained having good adherence.

VIII. 20 parts of compound no. 1 is intimately mixed with 2 parts of the calcium salt of dodecylbenzenesulfonic acid, 8 parts of a fatty alcohol polyglycol ether, 2 parts of the sodium salt of a phenolsulfonic acid-urea-formaldehyde condensate and 68 parts of a paraffinic mineral oil. A stable oily dispersion is obtained.

The active ingredients or agents may be applied pre- or postemergence. If certain crop plants tolerate the active ingredients less well, application techniques may be used in which the herbicidal agents are sprayed from suitable equipment in such a manner that the leaves of sensitive crop plants are if possible not touched, and the agents reach the soil or the unwanted plants growing beneath the crop plants (post-directed, lay-by treatment).

The amount of active ingredient applied depends on the time of the year, the objective to be achieved and the growth stage of the plants, and varies from 0.1 to 5 kg/ha and more, but is preferably from 1 to 3 kg/ha.

The herbicidal action of compounds of the formula I and Ia is demonstrated in greenhouse experiments.

The vessels employed were plastic flowerpots having a volume of 300 cm³, and which were filled with a sandy loam containing about 1.5% humus. The seeds of the test plants were sown shallow, and separately, according to species. For the preemergence treatment, the active ingredients were applied to the surface of the soil immediately after the seeds had been sown. The compounds were emulsified or suspended in water as vehicle, and sprayed through finely distributing nozzles. The application rate was 3.0 kg of active ingredient per hectare. After the agents had been applied, the vessels were lightly sprinkler-irrigated to induce germination and growth and to activate the chemical agents. Transparent plastic covers were then placed on the vessels until the plants had taken root. The cover ensured uniform germination of the plants, insofar as this was not impaired by the chemicals.

For the postemergence treatment, the plants were first grown in the vessels to a height of from 3 to 15 cm, depending on growth form, before being treated. For this treatment, either plants which had been sown directly in the pots and grown there were selected, or plants which had been grown separately as seedlings and transplanted to the experiment vessels a few days before treatment. No covers were placed on the pots in this treatment method. The application rates for postemergence treatment varied from ingredient to ingredient, and were 1.0, 2.0 and 3.0 kg of active ingredient per hectare.

The pots were set up in the greenhouse--species from warmer areas at from 20° to 35° C., and species from moderate climates at 10° to 20° C. The experiments were run for from 2 to 4 weeks. During this period, the plants were tended and their reactions to the various treatments assessed. The scale used for assessment was 0 to 100, 0 denoting no damage or normal emergence, and 100 denoting nonemergence or complete destruction of at least the visible plant parts.

The test plants employed were Amaranthus spp. Beta vulgaris, Chenopodium album, Ipomoea spp., Galium aparine, Lolium multiflorum, Sinapis alba, Solanum nigrum, Triticum aestivum, Urtica urens, and Viola tricolor.

On postemergence application of 3.0 kg of active ingredient per hectare in the greenhouse, for example compound no. 50 had a good herbicidal action.

On preemergence application of 3.0 kg of active ingredient per hectare, for instance compounds nos. 41, 64, 75, 77 and 101 combated broadleaved plants. Compounds nos. 77 and 78 also combated at lower rates unwanted broadleaved plants selected by way of example, without damaging the crop plants.

In view of the many application methods possible, the compounds according to the invention, or agents containing them, may be used in a large number of crop plants for removing unwanted plant growth.

The following crop plants may be mentioned by way of example:

    ______________________________________                                         Botanical name      Common name                                                ______________________________________                                         Allium cepa         onions                                                     Ananas comosus      pineapples                                                 Arachis hypogaea    peanuts (groundnuts)                                       Asparagus officinalis                                                                              asparagus                                                  Avena sativa        oats                                                       Beta vulgaris spp. altissima                                                                       sugarbeets                                                 Beta vulgaris spp. rapa                                                                            fodder beets                                               Brassica napus var. napobrassica                                               Brassica napus var. rapa                                                                           turnips                                                    Camellia sinensis   tea plants                                                 Carthamus tinctorius                                                                               safflower                                                  Carya illinoinensis pecan trees                                                Citrus limon        lemons                                                     Citrus maxima       grapefruits                                                Citrus reticulata   mandarins                                                  Citrus sinensis     orange trees                                               Coffea arabica (Coffea canephora,                                                                  coffee plants                                              Coffea liberica)                                                               Cynodon dactylon    Bermudagrass in                                                                turf and lawns                                             Daucus carota       carrots                                                    Elais guineensis    oil palms                                                  Fragaria vesca      strawberries                                               Glycine max         soybeans                                                   Gossypium hirsutum  cotton                                                     (Gossypium arboreum                                                            Gossypium herbaceum                                                            Gossypium vitifolium)                                                          Helianthus annuus   sunflowers                                                 Helianthus tuberosus                                                           Hevea brasiliensis  rubber plants                                              Hordeum vulgare     barley                                                     Humulus lupulus     hops                                                       Ipomoea batatas     sweet potatoes                                             Juglans regia       walnut trees                                               Lens culinaris      lentils                                                    Linum usitatissimum flax                                                       Lycopersicon lycopersicum                                                                          tomatoes                                                   Malus spp.          apple trees                                                Manihot esculenta   cassava                                                    Medicago sativa     alfalfa (lucerne)                                          Mentha piperita     peppermint                                                 Musa spp.           banana plants                                              Nicothiana tabacum  tobacco                                                    (N. rustica)                                                                   Olea europaea       olive trees                                                Oryza sativa        rice                                                       Panicum miliaceum                                                              Phaseolus lunatus   limabeans                                                  Phaseolus mungo     mungbeans                                                  Phaseolus vulgaris  snapbeans, green beans,                                                        dry beans                                                  Pennisetum glaucum                                                             Petroselinum crispum                                                                               parsley                                                    spp. tuberosum                                                                 Picea abies         Norway spruce                                              Abies alba          fir trees                                                  Pinus spp.          pine trees                                                 Pisum sativum       English peas                                               Prunus avium        cherry trees                                               Prunus domestica    plum trees                                                 Prunus dulcis       almond trees                                               Prunus persica      peach trees                                                Pyrus communis      pear trees                                                 Ribes sylvestre     redcurrants                                                Ribes uva-crispa    gooseberries                                               Ricinus communis    castor-oil plants                                          Saccharum officinarum                                                                              sugar cane                                                 Secale cereale      rye                                                        Sesamum indicum     sesame                                                     Solanum tuberosum   Irish potatoes                                             Sorghum bicolor (s. vulgare)                                                                       sorghum                                                    Sorghum dochna                                                                 Spinacia oleracea   spinach                                                    Theobroma cacao     cacao plants                                               Trifolium pratense  red clover                                                 Triticum aestivum   wheat                                                      Vaccinium corymbosum                                                                               blueberries                                                Vaccinium vitis-idaea                                                                              cranberries                                                Vicia faba          tick beans                                                 Vigna sinensis (V. unguiculata)                                                                    cow peas                                                   Vitis vinifera      grapes                                                     Zea mays            Indian corn, sweet                                                             corn, maize                                                ______________________________________                                    

To increase the spectrum of action and to achieve synergistic effects, the compounds according to the invention, or herbicidal agents containing them, may be mixed and applied together with numerous representatives of other herbicidal or growth-regulating active ingredient groups. Examples of suitable mixture components are diazines, 4H-3,1-benzoxazine derivatives, benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates, thiolcarbamates, halocarboxylic acids, triazines, amides, ureas, diphenyl ethers, triazinones, uracils, benzofuran derivatives, cyclohexane-1,3-dione derivatives, etc.

It may also be useful to apply the compounds of the formula I and Ia, either alone or in combination with other herbicides, in admixture with other crop protection agents, e.g., agents for combating pests or phytopathogenic fungi or bacteria. The compounds may also be mixed with solutions of mineral salts used to remedy nutritional or trace element deficiencies. Non-phytotoxic oils and oil concentrates may also be added. 

We claim:
 1. An aminothiadiazole of the formula ##STR18## where R¹ and R² independently of one another are each hydrogen, C₁ -C₁₀ -alkyl, C₃ -C₈ -cycloalkyl, C₂ -C₅ -alkoxyalkyl, phenyl, benzyl, 2-phenylethyl, or R¹ and R² together form a butylene, pentylene, 1,4-dimethyl-3-oxapentylene or 2,4-dimethyl-3-oxapentylene group, A is an alkylene chain of 2 to 4 carbon atoms which is unsubstituted or substituted by C₁ -C₄ -alkyl, Z is oxygen, n is 0 or 1, X is halogen, cyano, nitro, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, C₁ -C₄ -haloalkyl, C₁ -C₄ -alkylthio, C₁ -C₄ -alkylsulfonyl, C₃ -C₆ -cycloalkyl, phenyl or unsubstituted or halogen-substituted aryloxy and m is 0, 1, 2, 3 or 4, and where the radical ##STR19## can be replaced by naphthyl which is unsubstituted or substituted by halogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, with the proviso that R¹ and R² are not both hydrogen.
 2. An aminothiadiazole of the formula I as defined in claim 1, where R¹ is hydrogen, R² is C₁ -C₄ -alkyl, A is an alkylene chain of 2 to 4 carbon atoms, n is 0 or 1, Z is oxygen, X is halogen or C₁ -C₄ -alkyl, and m is 1, 2 or
 3. 3. 2-[4-(2-Methyl-phenoxy)-n-butanyl]-5-methylamino-1,3,4-thiadiazole.
 4. An aminothiadiazole of the formula I as defined in claim 1, wherein n is
 1. 5. A compound of the formula I as defined in claim 1, which is (5-[5-(4-methyl-phenoxy--n-pentyl]-2-methylamino-1,3,4-thiadiazole.
 6. An aminothiadiazole of the formula ##STR20## where R¹ and R² independently of one another are each hydrogen, C₁ -C₁₀ -alkyl, C₃ -C₈ -cycloalkyl, C₂ -C₅ -alkoxyalkyl, phenyl, benzyl, 2-phenylethyl, or R¹ and R² together form a butylene, pentylene, 1,4-dimethyl-3-oxapentylene or 2,4-dimethyl-3-oxapentylene group, A is ethylene, methylethylene, dimethylethylene, propylene, methylpropylene, butylene, or methylbutylene, Z is oxygen, n is 0 or 1, X is halogen, cyano, nitro, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, C₁ -C₄ -haloalkyl, C₁ -C₄ -alkylthio, C₁ -C₄ -alkylsulfonyl, C₃ -C₆ -cycloalkyl, phenyl or unsubstituted or halogen-substituted aryloxy and m is 0, 1, 2, 3 or 4, with the proviso that R¹ and R² are not both hydrogen.
 7. A herbicide containing inert additives and an aminothiadiazole of the formula I as defined in claim
 1. 8. A herbicide as defined in claim 7, where the aminothiadiazole of the formula I is one in which R¹ is hydrogen, R² is C₁ -C₄ -alkyl, A is an alkylene chain of 2 to 4 carbon atoms, n is 0 or 1, Z is oxygen, X is halogen or C₁ -C₄ -alkyl, and m is 1, 2 or
 3. 9. A herbicide containing an inert carrier and/or diluent and from 0.1 to 95% by weight of an aminothiadiazole of the formula ##STR21## where R¹ and R² independently of one another are each hydrogen, C₁ -C₁₀ -alkyl, C₃ -C₈ -cycloalkyl, C₂ -C₅ -alkoxyalkyl, phenyl, benzyl, 2-phenylethyl, or R¹ and R² together form a butylene, pentylene, 1,4-dimethyl-3-oxapentylene or 2,4-dimethyl-3-oxapentylene group, A is an alkylene chain of 1 to 8 carbon atoms which is unsubstituted or substituted by C₁ -C₄ -alkyl, Z is oxygen or sulfur, n is 0 or 1, X is halogen, cyano, nitro, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, C₁ -C₄ -haloalkyl, C₁ -C₄ -haloalkoxy, C₁ -C₄ -alkylthio, C₁ -C₄ -alkylsulfonyl, C₃ -C₆ -cycloalkyl, phenyl or unsubstituted or halogen-substituted aryloxy and m is 0, 1, 2, 3 or 4, and where the radical ##STR22## can be replaced by naphthyl which is unsubstituted or substituted by halogen, C₁ -C₄ -alkyl or C₁ -C₄ -alkoxy, with the proviso that R¹ and R² are not both hydrogen when n is 0 and A is --CH₂ --.
 10. A herbicide as defined in claim 9, where the aminothiadiazole of the formula Ia is one in which R¹ is hydrogen, R² is C₁ -C₄ -alkyl, A is an alkylene chain of 1 to 4 carbon atoms, n is 0 or 1, Z is oxygen, X is halogen or C₁ -C₄ -alkyl, and m is 1, 2 or
 3. 11. A process for combating unwanted plant growth, wherein a herbicidally effective amount of an aminothiadiazole of the formula I as defined in claim 1 is allowed to act on the plants and/or their location.
 12. A process for combating unwanted plant growth, wherein a herbicidally effective amount of an aminothiadiazole of the formula Ia as defined in claim 9 is allowed to act on the plants and/or their location. 